WIA GC/1887/10 | Ruben, Paul to Warburg, Aby 15/10/1887 | mentions Ernst Levy, Wilhelm Kiesselbach, John [Johann Nicolaus] Hertz, Johannes [Hans] Nippen... |
WIA GC/1888/10 | Kiesselbach, Wilhelm to Warburg, Aby 14/10/1888 | thanks him for Warburg's photograph; wishes him a good new term at university |
WIA GC/1888/11 | Warburg, Aby to Kiesselbach, Wilhelm [1888] | invitation to join [ Max L.] Strack, [Johann Nicolaus] Hertz and Warburg the next day in the pub... |
WIA GC/1889/17 | Kiesselbach, Wilhelm to Warburg, Aby 06/05/1889 | a detailed appraisal of the suitability of N. to become a member of the student fraternity... |
WIA GC/1891/10 | Nirrnheim, Hans to Warburg, Aby 31/12/1891 | New Year greetings and hopes that he might finish his studies; his father is very ill; Wilhelm... |